The President's Address. By Lord Avebury. 157 



In other cases no doubt the awns serve to catch the wind, and 

 thus move the seed. 



Some grasses {Setaria, Oryza) have barbed bristles, which no 

 doubt adhere to passing animals. In others the awns serve for 

 this purpose. 



In some species the awns are delicately hygroscopic, and so 

 serve to move the seeds along the ground, and finally to bury 

 them, as will be mentioned later on. 



In many grasses the glumes are fringed with fine hairs (Cala- 

 magrostis), and in others they are widened out and thus serve the 

 same purpose. Briza (the shaking grasses), and Melica may be 

 mentioned as cases in point. They are always scabrid, or barbed, 

 with short, stout ascending points. The empty glumes occasionally 

 bear awns, but in most cases these are confined to the flowering 

 glumes, and remain upon them while being disseminated, and to 

 aid this most important object would seem to be their chief function 

 in the economy of the grasses. 



The empty glumes areawned in Panicum Crus-galli (one glume) 

 Phleum pratense, P. alpinum, P. phleoides, Anthoxauthum odoratum 

 (on a second pair of empty glumes inside the two lower), A. aris- 

 tatum and Polypogon monspeliensis. 



The flowering glumes are awned in all the species of Alope- 

 curus, Agrostis setacea, A. canina, Calamagrostis epigcios, C. canes- 

 cens, Gastridium lendigerum, Apera Spica-venti, A. interrupta, 

 Ammophila (very short), Aira caryophyllea, A. praecox, Cory- 

 nephorus canescens, Deschampsia caespitosa, D. alpina, D. Jlexuosa, 

 Holcus mollis, H. lanatus, Trisetum flavescens, all the species of 

 Avena, Arrhenatherum elatius, Seslcria caervlea, Cynosurus 

 cristatus, C. echinatus, Koeleria gracilis var. Iritannica, Dactyl's, 

 Festuca Iromoides, F. ovina, F. rubra, all the species of Bromus, 

 Brachypodium, Agropyrum caninum, Lolium perenne var. mulii- 

 jlorum, Lolium perenne var. aristatum, L. temidentum, and Nardus. 

 The awn of Corynephorus is of remarkable form, being clavate, 

 bent and bearded above the base. Although Phragmites has no 

 awns, the flowering glumes are slender and elongated. 



Conclusion. 



Having thus rapidly and very imperfectly run through our 

 families of English flowering plants, and incidentally mentioned 

 some others, I may, in conclusion, ask your indulgence while I 

 make some general observations on seeds. 



First, then, as regards size. Why are some large and few, and 

 others so very numerous and small ? 



If we could imagine a state of things in which every seed 

 grew and attained maturity, it would be sufficient to keep up the 

 number of any given species existing at any time if each plant 



